The present invention relates to torque transmitting devices in general, and more particularly to improvements in means for damping vibrations which tend to develop when one of two or more rotary assemblies of a torque transmitting device turns relative to the other assembly or assemblies. Typical examples of such torque transmitting devices are clutch plates which are used in friction clutches of automotive vehicles to transmit torque from a driving member to a driven member, e.g., from the crankshaft of an internal combustion engine to the input shaft of a change-speed transmission.
It is known to assemble a friction clutch plate of several (at least three) assemblies one of which is the input assembly and can comprise a disc-shaped carrier of friction linings, another of which is the output assembly and can comprise a rotary hub and a flange on the hub, and a third of which can comprise at least one disc-shaped or plate-like friction generating component. One or more coil springs or analogous energy storing means are interposed between the input and output assemblies to yieldably oppose the limited amount of angular movement between such assemblies, and the third assembly is installed in the path of transmission of power between the input and output assemblies to offer a resistance to relative angular movement at least during part of rotation of the input assembly with reference to the output assembly and/or vice versa. A second component of the third assembly stores energy and urges the aforementioned friction generating component against one of the input and output assemblies. The energy storing component reacts against the other of the input and output assemblies.
A clutch plate of the just outlined character is disclosed, for example, in German Offenlegungsschrift No. 1,600,194. In the clutch plate of this German publication, the carrier of friction linings is non-rotatably secured to a disc-shaped cover, and one side of the cover is adjacent to a friction generating component which is disposed between two friction pads. The other side of the cover is adjacent to the energy storing component which is stressed in the axial direction and constitutes a dished spring serving to insure the generation of necessary friction which opposes the angular movement between the carrier of friction linings and the hub. The radially outermost portion of the energy storing component reacts against the cover, and its innermost portion bears against an adjustable nut which meshes with the hub. The latter extends through the cover and has an enlarged portion or boss at that side of the cover which faces away from the energy storing component. The friction generating component is confined between the boss and the respective side of the cover, i.e., one of the aforementioned friction pads bears against the radially outwardly extending boss and the other friction pad bears against the cover. The friction generating component has edge faces which engage the energy storing means between the input and output assemblies of the clutch plate.
A drawback of the just discussed conventional clutch plate is that it is expensive, mainly because it comprises a relatively large number of complex parts such as an externally threaded hub with a boss, an internally threaded nut, and others. Furthermore, the assembling of the just discussed clutch plate takes up a substantial amount of time. Moreover, the vibrationdamping unit takes up a considerable amount of space, as considered in the axial direction of the clutch plate. Such space is not available in all friction clutches so that the clutch plate of the German publication can be used only in certain types of clutches. Still further, the weight and hence the inertia of the conventional clutch plate is substantial which is highly undesirable, e.g., as regards the synchronizing devices for change-speed transmissions in automotive vehicles.